Cupriferous azo-dyestuffs of the stilbene series



UNITED STATES P" CUPRIFEROUS AZO-DYESTUFFS OF THE STILBENE SERIES Raymond Gunst, Basel, Switzerland, assignor to Ciba Limited, Basel, Switzerland No Drawing. Application March 23, 1950, Serial No. 151,555. In Switzerland April 28, 1949 I 2 Claims. (01. 260-143) 1 2 TENT OFFICE According to this invention valuable new and, when necessary, also with an aminoazo cupriferous azo dyestuffs of the stilbene series dyestuff of the general formula are made by treating a dyestuff of the general formula 5 (3) R1-N=N-Rz--=NH2 I I YQCH=CHZN=NJ in Which R1 represents the radical of a 'diazo I component and R2 represents an aromatic radical SOSH 11088 J; of the benezene series containing the groups -N=N and -NH2 in para-position relatively C to one another. 7 As amino'azo dyestuffs of the general Formula a V 3 there may be used, among others, the aminoazo dyestufi of the Formula 2, in which case a product corresponding to the formula mt N v N/ NE in which X represents a hydrogen atom or an is produced, X and Z having the previously-r --O-CI-I3 group, Z represents a, nitrogenconcited significances; but other aminoazo dyestufis taining bridge such as an azoxy or azorgroup, and are also suitable for this purpose. Y represents a nitro group or the radical When the 4:4'-dinitrosti1bene-2:2'-disulfonic R1--N=N--R2Z-- in which R1 represents the acid is condensed on one side only with the radical of a diazo component, R2 represents an aminoazo dyestuif of the Formula 2, the conaromatic radical of the benzene series containdensation of the second nitro group with an ing the groups N=N- and Z in para-position aminoazo dyestuii of the Formula 3, which, if relatively to one another and Z represents a 1 desired, may also be the compound of the Formula nitrogen-containing bridge such as an azoxy or 2 may be complete or incomplete, that is to say,

are group with an agent yielding. copper until less than one mol, for example about of a mol, any methoxy group present in an ortho-hydroxyof the aminoazo dyestufi of the Formula 3 may ortho'-methoxy-azo grouping has been split up. be used.

The azo dyestuffs oi the above formula used as The aminoazo ye-St ff f t la 2 y starting materialsin the process may be prepared be p ep d by p g diEtZotiZed 2-(3'aminoby condensing one mol of 4: l'-dinitrosti1beneydrOXyl h Y -benziifiidaz01e in an acid 2:2-disulfonic acid with onemol of the aminomedium, for example, an acet c acid m d um azo dyestufi of the formula with l-amino-s-methoxy-benzene or l-amino- 2:5 dimethoxybenzene. 2 (3 amino 4-hy- 0- H0 droxyphenyl) -benzimidazole may be obtained by I condensing 3-nitro-4-hydroxy-1-benzcic acid G- chloride with lzz-diamino-benzene, and, reducing to an amino group the nitro group in the 2-(3'- X nitroy-hydroxyphenyl) -benzimidazo1e so obtamed. The condensations of 4:4'-dinitrostilbene-2:2- N NH disulfonic acid with the amino-monoazo dyestuffs v i l of the Formulae 2 and 3 are advantageously conducted in an aqueous medium and in the presence of an alkali hydroxide". Good results are ob- 3 tained, for example, by reacting the substances together in a dilute solution of alkali hydroxide, for example, of 2-8 per cent. strength, for a prolonged period, for example, 5-20hours at a raised temperature, for example, in an open vessel at the boiling temperature of the reaction mixture and under reflux or at a higher temperature under pressure. When 4:4-dinitrostilbene-2:2- disulfonic acid is to be condensed not only with the aminoazo dyestufr of the Formula 2 but also with another aminoazo dyestuff of the Formula 3, it has generally been found advantageous to carry out both condensations in a single operation.

It can be seen from the above that the symbol Z herein denotesanitrogen-containing bridge such as the different bridges formed by the reaction of the nitro group in 4-position to the CH=CI-I- group of the stilbene compound with the primary amino group of the aminoazo dyestuff, i. c. more particularly an azo or azoxy group. When the molecule contains two groups Z they may be both azo or both azoxy groups or an azo group and also an azoxy group. It is also possible that mixtures of different compounds of this kind are formed.

The dyestuff of the general Formula 1 are treated with an agent yielding copper until the methoxy group or groups present in the orthohydroxy-ortho'-methoxyazo grouping or groupings have been split up completely with the formation of the complex copper compound. As agents yielding copper there may be used in or divalent copper such as cuprous chloride or cupric sulfate, and also compounds which contain copper in complex union. For this purpose cuprammine complexes are especially suitable, for example, the complex copper compounds obtainable from ammonia, alkyl amines such as ethylamine, morpholine, pyridine 0r piperidine. In order to ensure that the methoxy group or groups are completely split up with the formation of the copper complex in the stilbene-azo-dyestuffs used as starting materials in the present invention, it is generally necessary to conduct the treatment with the agent yielding copper at a raised temperature, for example, at about 90 C., and for a period of several hours. It is of advantage to work in an aqueous medium. If desired the treatment with the agent yielding copper may be conducted in the presence of a suitable addition. As such additions there may be mentioned, bases such as ammonia or organic bases, and, when a cuprammine complex is used, advantageously an excess of the same base as is present in the molecule of the cuprammine complex used. Other acid-binding agents may also be used. In general very good results are obtained by carryingout the treatment with an agent yielding copper by the process of U. S. patent application Ser. No. 778,734 (now U. S. Pat. No. 2,536,957), for example in the presence of an ethanolamine. The cupriferous azo dyestuffs of the stilbene series ob- 4 tainable by the present invention are new and correspond to the general formula in which X represents a hydrogen atom or an 0CH3 group, Z represents a nitrogen-containing bridge such as an azoxy or azo group, and Y represents a nitro group or the radical R1N=NR2Z, in which R1 represents the radical of a diazo component, R2 represent an aromatic radical of the benzene series containing the groups -N=N- and Z in para-position relatively to one another, and Z represents a nitrogencontaining bridge such as an azoxy or azo group, and in which the linkage R1N=NR2 may be present in the form of the complex linkage Where the azo dyestufl corresponds to Formula 4 and X stands for hydrogen, the cupriferous dyestufl" will correspond to the formula The cupriferous azo dyestuffs obtainable by the present invention are suitable for dyeing or printing a very wide variety of materials, for example, materials of animal origin such as wool or leather. Owing to their good afiinity for vegetable fibers they are especially suitable for dyeing or printing cellulosic materials, such as linen, cotton, or artificial silk or staple fibers of regenerated cellulose.

The yellow-brown to brown-violet to olive dyeings obtainable on cellulose fibers with the new cupriferous azo dyestuffs are distinguished, above all, by their good fastness to washing and excellent fastness to light.

The following examples illustrate the invention, the parts being by weight unless otherwise stated and the relationship of parts by weight to parts by volume being the same as that of the kilogram to the liter:

Example 1 21.1 parts of 2-(3'-amino-4'-hydroxyphenyl)- benzimidazole are dissolved in 150 parts of water with the addition of 30 parts of hydrochloric acid of 30 per cent. strength, and diazotized by the addition of a solution of 6.9 parts of sodium nitrite in 50 parts of water at 0 C., and the finished diazo compound is separated by filtration. For coupling, 12.3 parts of l-amino-B-methoxybenzene are dissolved in 100 parts of acetic acid of per cent strength and the solution is coupled with the diazo compound which is stirred with a and 1-amino-2:5-dimethylbenzene are condensed with 47.5 parts of the disodium salt of 4:4-dismall quantity of water and ice. After stirring nitrostilbene-2:2'-disulfonic acid in 1800 parts of for several hours the reaction mixture is heated water with the addition of 160 parts of sodium to 50 0., and the dyestuff formed is precipitated 5 hydroxide solution of 30 per cent. strength by completely, if necessary by the addition of sodium maintaining the reaction mixture at the boil unchloride, and separated by filtration. der reflux for 1-8 hours while stirring.

The resulting monoazo dyestuff is introduced By adding sodium chloride and neutralizing a into a stirring vessel provided with a reflux conpart of the excess of alkali with hydrochloric denser and containing 1000 parts of water, and is acid the condensation product formed is preneutralized with sodium hydroxide solution at cipitated, and is then separated by filtration. the same time. 24 parts of the disodium salt of In order to convert the condensation product l:4'-dinitrostilbene-2:2-disulfonic acid and 100 into its complex copper compound it is dissolved parts of a sodium hydroxide solution of 30 per in 12 times its weight of water at 90 C. with the cent. strength are then added and the reaction 5 addition of a small amount of ammonia. To the mixture is maintained at the boil ior 2% hours solution is added a mixture of 50 parts of a 2N- while stirring and refluxing. solution of copper sulfate and 50 parts of an By adding sodium chloride and neutraiizing a ammonia solution of 25 per cent. strength, and part of the excess of alkali with hydrochloric acid the whole is maintained at 90-95 C. for 5 hours the condensation product formed can be sep- 29 While stirring. arated from the reaction mixture. The complex copper compound, which is pre- In order to convert it into the complex copper cipitated from solution by means of sodium chlocompound the condensation product, separated ride and dried, is a dark brown powder which by filtration is suspended in times its weight dissolves in water with a brown coloration and of water, 40 parts of ammonia solution of per dyes cotton beautiful brown tints which are'fast cent. strength and 40 parts of monoethanolamine to washing and light. are added and the whole is well stirred for By replacing the 39.0 parts of the monoazo minutes at 90 C. The homogeneous mixture is dyestuff from diazotized Z-aminonaphthaleneintroduced into a stirring vessel provided with a 4:8-disulfonic acid and l-amino-2z5-dimethylreflux condenser, 50 parts of a ZN-solution of 30 benzene by the corresponding quantities of the copper sulfate and 50 parts of an ammonia solumonoazo dyestuiis prepared from diazotized 2- tion of 25 per cent. strength are added, and the aminonaphthalene-4:8-disulfonic acid and 1- whole is maintained at 90-95 C. for 12 hours amino-3-methylbenzene or l-amino-Z-methoxywhile stirring. The complex copper compound benzene, and otherwise proceeding in the manner may be precipitated by salting out and separated 5 described in this example, there are obtained by filtration. It is a dark powder which discupriferous dyestuffs which dye cotton somewhat solves in water with a violet coloration and dyes more yellowish or distinctly more reddish-brown cotton violet brown tints which are fast to washtints, respectively. ing and light.

The 2- (3-amino-4'-hydroxyphenyl) -benzimid-- azole may be prepared as follows:

54 parts of 1 :Z-diaminobenzene are dissolved in Example 3 A dyebath is prepared which contains in 3000 parts of water 2 parts of the dyestuff obtained 500 parts by volume of chlorobenzene with the as described in Example 1 and 30 parts of erys addition of 120 part by Volume 0f pyridine- At talline sodium sulfate. 100 parts of cotton are 60 C. there are added in portions, Wh e St i entered into the dyebath at C., the tempera 1 P s Of 0- y O Y- acid ture is increased to 0., and dyeing is carried chloride. The mixture is then heated to the boil on t t temperature for one hetm The t. and maintained for 2 hours at h boiling ton is then rinsed and dried. It is dyed a brown perature. The chlorobenzene and pyridine are 1 t t t and t dyeing i distinguished by then distilled off with steam. By acidifying the 50 good fastness t ashing and h m,

residue of the distillation the resulting 2-(3'- Having thus disclosed t invention, t I nitro-4=-hydroxyphenyl) -benzimidazole is preclaim i cipitated in a well filterable form. The nitro A cuprjferous azo dyestufi of t Stilhehe group in the product so obtained is reduced to an Series corresponding t t formula,

N=NOZ CH=CH amino group, for example, by catalytic reduction by means of a nickel catalyst in an aqueous alcoholic suspension.

Erample 2 34.5 parts of the monoazo dyestufi obtained as described in the first paragraph of Example 1 and 39.0 parts of the monoazo dyestufi from diazotized 2-aminonaphthalene-4 S-disulfonic acid No references cited. 

1. A CUPRIFEROUS AZO DYESTUFF OF THE STILBENE SERIES CORRESPONDING TO THE FORMULA 